NEW HAVEN, CT & SOUTH SAN FRANCISCO, CA, USA I July 06, 2023 I Simcha Therapeutics (“Simcha”), a clinical-stage immunobiology company pioneering first-in-class cytokine treatments in cancer, today announced that the first patient has been dosed in a Phase 1/2 clinical trial of ST-067, Simcha’s decoy resistant IL-18 agent, in combination with Merck’s anti-PD-1 therapy, KEYTRUDA® (pembrolizumab), in patients with advanced solid tumors.

The Phase 1/2 open-label, dose-escalation study is evaluating ST-067 in combination with pembrolizumab in a variety of solid tumors (NCT04787042). The objective of the study is to determine the maximum tolerated dose (MTD), the recommended Phase 2 dose (R2PD) and preliminary activity of ST-067 in combination with pembrolizumab. Secondary endpoints include assessment of safety, pharmacokinetics, pharmacodynamics and immunogenicity.

“We have observed encouraging anti-tumor activity in preclinical studies combining our decoy-resistant IL-18 with PD-1 inhibitors, and we look forward to now studying this combination in the clinic,” said Sanuj Ravindran, M.D., CEO of Simcha Therapeutics. “KEYTRUDA has become the standard of care for many cancer patients, and we believe adding ST-067 could further improve clinical outcomes. This combination has the potential to become a powerful new therapeutic option for patients and physicians.”

KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About ST-067

ST-067 is the first “decoy-resistant” variant of IL-18, designed to be impervious to the decoy receptor IL-18BP, which blocks IL-18 from interacting with its receptor. ST-067 has been shown in preclinical studies to maintain strong immune stimulation in the tumor microenvironment and is currently in Phase 1/2 clinical development as both a monotherapy and in combination with KEYTRUDA® (pembrolizumab).

About Simcha Therapeutics

Simcha Therapeutics is a clinical-stage immunobiology company pioneering the development of first-in-class engineered cytokine therapeutics with transformational promise for patients. The company is built on a foundation of scientific rigor to overcome biological challenges in clinically translatable pathways, exemplified by the first decoy-resistant interleukin-18 (IL-18). By unlocking the potential of IL-18, Simcha is developing its lead program (ST-067) as monotherapy and in combination with potentially several other anticancer agents. ST-067 is currently being studied both as a monotherapy and in combination with KEYTRUDA® (pembrolizumab) in Phase 1/2 clinical trials, in patients with solid tumors and who have progressed on other immunotherapeutic agents. Simcha is seeking to explore additional modalities for IL-18-based therapeutics and capture the full potential of this potentially transformational cytokine. For more information, please visit

SOURCE: Simcha Therapeutics